There is an adjustable crossover which will cut out the unwanted high frequencies, resulting in a clean signal to again reduce distortion and provide the best sound quality possible. Each subwoofer size varies in power and frequency range. CASA10 (10) - 300W RMS / 60 - 150Hz. CASA12 (12) - 400W RMS / 55 - 150Hz. CASA15 (15) - 500W RMS / 50 - 150Hz.The Citronic CASA Subwoofers are built to last. They are constructed of hard-wearing 15mm MDF and coasted in a textured paint finish, which should offer some resistance to unwanted spills - ideal in a bar scenario! The front grille is made from steel and not only adds to the solid construction but improves the sound quality too. There is a 35mm pole mount socket on top for connecting a PA speaker, and two handles for easy transportation. On the rear of the CASA Subwoofers are 2x balanced XLR/1/4 Jack Combi line inputs, and 2x balanced XLR outputs. There is a phase switch and master volume control, as well as an XLR link connection to carry the signal to additional speakers. Class-D Amplification - Ideal for low frequencies. 15mm MDF cabinets with hard-wearing paint finish. 2 x side carry handles. L&R output link to connect to other speakers.